The diacetyl rhein of formula (II) ##STR2## is a drug having antiarthrosis activity and such an activity is claimed by the same Applicant in Italian patent application 1,098,332.
The diacetylrhein used as such has the drawback to be water insoluble,therefore it cannot be administered by parenteral or by intraarticular route. but it can only be given by oral route.
The oral therapeutic method has the disadvantage. that in order to be effective, high amount of diacetylrhein must be administered to the patient affected by artrhosis, and for a long time period.